No, that wasn't a joke......if you want to keep really accurate tabs on your equipment, nothing beats the exergen. If you look around, you can get them for much less than $270. I paid $180 for mine, brand new, about 5 years ago.
I've compared mine to many different budget friendly temps guns, like the one you have in the link. I've seen differences as little as 5 degrees, to as much as 40 deg. The low cost ones have consistently read lower than the Exergen. I've also sent mine in for calibration twice.....both times there was no changes needed.
For nitro, even if you're only keeping track of temps at the end of a race to make sure it's not getting too high, there's a big difference between 250F and 290F. On the flip side, it's not just for nitro either. If you want to make sure your electric equipment is running at peak performance, you need to have accurate temp readings on the motor and ESC.
The folks who don't care much about equipment temps will never be convinced that spending close to $200 for a temp gun is worth it. For the folks who believe in keeping accurate measurements, nothing else but an Exergen is acceptable.
Just an FYI though, the Trakpower (formerly O'Donnell branded) temp gun has consistently been the farthest off from the Exergen (generally reading between 20 and 40 degrees lower). The TG1 from tempgun.com has been the closest (generally within 5 degrees F). I have one of those in my tool box as well, just in case something happens to my Exergen.
(Here's a link to it)